Diagnosis

Discussion

Catheter malfunction due to poor flow is a commonly encountered problem. When this occurs soon afterplacement, the etiology is typically technical, while delayed occurrences are usually due to thrombus formation. Although numerous types of thrombus exist, the most common is the fibrin sheath. All catheters eventually develop a fibrin sheath, but the impact is most significant for apheresis and hemodialysis catheters, which must sustain flow rates greater than 300mL/min through the arterial port. When end or side holes of the catheter are covered by the sheath, the sheath acts like a one way valve – there is difficulty aspirating blood, but the catheter can still be injected with relative ease.